As a way of accessing the network by the user, WLAN has incomparable advantages of simple wiring, convenient movement and the like compared to wired access. With evolution of technology, the bandwidth of the WLAN increases gradually. But as to QoS, only Enhanced Distributed Channel Access (EDCA) QoS in IEEE802.11e can meet the requirements on the transmission of data services, and is in the full service (data, voice and video etc.), the QoS is obviously insufficient.
EDCA QoS has the following limitations: 1, there are only four message categories, which are respectively AC_BE, AC_BK, AC_VI and AC_VO, and correspondingly priority queue only has four levels, which cannot meet the requirements of full-service scenarios; 2, it is a relative priority in EDCA QoS; in a severe environment, high priority service will be also influenced; for example in home applications, when Internet Protocol Television (IPTV) service and service of surfing Internet are carried out simultaneously, user cares more about the IPTV service, and cannot accept appearance of mosaics or video pause or delay, but can stand the influence of service of surfing Internet relatively. At present, EDCA QoS cannot completely ensure high priority service, for example cannot ensure the preference of the IPTV service and the like.